Method for activating high-sulfur bauxite by means of low-temperature roasting desulfurization method

A technology of high-sulfur bauxite and bauxite, applied in chemical instruments and methods, separation methods, preparation of alkali metal aluminate/alumina/aluminum hydroxide, etc., can solve energy waste, gas-liquid mass transfer efficiency Poor, high roasting desulfurization temperature and other problems, to achieve the effect of reducing energy consumption and heat source cost

Active Publication Date: 2013-01-30
BEIJING UNIV OF CHEM TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method is easy to combine with the alumina production process, but there are the following problems: first, the use of fluidized bed roasting desulfurization has strict requirements on the uniformity of ore powder particles, which increases the cost; second, the roasting desulfurization temperature is too high, resulting in waste of energy and It is not conducive to the dissolution of aluminum; the third is to directly use the red mud slurry as the filler in the desulfurization packed tower for desulfurization of the roasting tail gas, the gas-liquid mass transfer efficiency is poor, and it is prone to blockage

Method used

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  • Method for activating high-sulfur bauxite by means of low-temperature roasting desulfurization method
  • Method for activating high-sulfur bauxite by means of low-temperature roasting desulfurization method

Examples

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Effect test

Embodiment 1

[0039] Example 1 Oxidative Roasting Desulfurization and Activation of High-sulfur Bauxite Powder Fluidized Furnace and Limestone Wet Purification of Roasting Tail Gas

[0040] Dry and grind the high-sulfur bauxite with an aluminum-silicon ratio of 7.1 and a sulfur content of 3.7%, and pass through 50 meshes to take the ore powder with a particle size of 2 , make the ore powder in the temperature range of 560~600°C for fluidized oxidative desulfurization and dehydration transformation activation, keep it in the fluidized bed furnace for 5~10 minutes, and the sulfur content of the ore powder will drop to 0.43% after roasting; press the roasted desulfurization ore powder With a sodium-aluminum ratio of 1.6, add lime equivalent to 4% of the bauxite content, dissolve in a solution with a caustic concentration of 240g / L at 240°C for 60 minutes, and the dissolution rate of alumina is 93.4%; use cold air The roasting desulfurization tail gas is cooled by a heat exchanger, the temperatu...

Embodiment 2

[0041] Example 2 Oxidative roasting desulfurization and activation of high-sulfur bauxite powder rotary kiln and purification of roasting tail gas by red mud method

[0042] Dry and grind the high-sulfur bauxite with an aluminum-silicon ratio of 8.1 and a sulfur content of 4.1%, and pass through 20 meshes to obtain ore powder with a particle size of 2 , make the ore powder in the temperature range of 500~535°C for fluidized oxidative desulfurization and dehydration transformation activation, keep it in the rotary kiln for 30~40 minutes, and the sulfur content of the ore powder will be reduced to 0.31% after roasting; the roasted desulfurization ore powder According to the sodium-aluminum ratio of 1.45, add lime equivalent to 4% of the bauxite content, dissolve in the eluate with a caustic concentration of 200g / L at 220°C for 90 minutes, and the dissolution rate of alumina is 93.1%. The air passes through the heat exchanger to cool the roasting desulfurization tail gas, and the ...

Embodiment 3

[0043] Example 3 Oxidative roasting desulfurization and activation of high-sulfur bauxite powder fluidized furnace and purification of roasting tail gas by red mud method

[0044] Dry and grind the high-sulfur bauxite with an aluminum-silicon ratio of 6.5 and a sulfur content of 2.1%, and pass through 80 mesh and 200 mesh respectively to obtain mineral powder with a particle size of 0.075~0.18mm; The air is heated by hot air at 750~850°C; after the ore powder is added to the fluidized bed, the hot air is added from the lower side of the fluidized bed, and the FeS in the ore powder is heated and ignited in the fluidized bed by hot air. 2 , so that the ore powder is activated by fluidized oxidation desulfurization and dehydration within the temperature range of 540~580°C, and kept in the fluidized furnace for 10~15 minutes, and the sulfur content of the ore powder is reduced to 0.22% after roasting; the roasted desulfurization ore powder is pressed With a sodium-aluminum ratio o...

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Abstract

The invention relates to a method for activating high-sulfur bauxite by means of a low-temperature roasting desulfurization method. The method which carries out oxidative desulfurization roasting on bauxite with 1 to 5 wt percent of sulfur content so that the bauxite can become material applicable to the Bayer process production of alumina is characterized in that the oxidative desulfurization temperature is controlled between 500 DEG C and 600 DEG C. More specifically, in a fluidized bed roaster or a rotary kiln, hot air which is 650 DEG C to 900 DEG C is utilized to heat dry-ground mineral powder. Not only is the sulfur content in the processed mineral powder decreased to be less than 0.5 percent, but also the organic matters in the mineral are completely oxidized to be decomposed, and meanwhile, because the roasting temperature is low, activated alumina can be prevented from being transformed to become over-stable. When the roasted bauxite is used in Bayer digestion, the digestion performance is improved, and the digestion rate of alumina is higher than 93 percent. After limestone suspension is cyclically sprayed or red mud suspension is sprayed to desulfurize the tail gas containing SO2 produced by oxidative desulfurization, the SO2 content can be decreased to be less than 300mg/m3, and thereby the tail gas comes up to the emission standard.

Description

technical field [0001] The invention belongs to the technical field of effective utilization of low-quality mineral resources, and mainly relates to a pre-desulfurization technical method for producing alumina by utilizing high-sulfur bauxite. Background technique [0002] Alumina is a bulk raw material for the production of aluminum metal. my country's annual output and consumption have exceeded 30 million tons, ranking first in the world. However, the high-quality bauxite resources used to produce alumina in my country are very limited, and about 200 million tons of high-sulfur diaspore-type bauxite with a sulfur content greater than 0.7wt% is urgently needed to be developed and applied. Sulfur in bauxite is mainly in the form of pyrite (FeS 2 ), and secondly exists in the form of sulfate, such ores generally coexist with a large amount of humic acid organic matter. At present, the main problem in the production of alumina with high-sulfur bauxite is that organic matter ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/06B01D53/80B01D53/50
Inventor 万平玉钮因键顾松青陈咏梅唐阳赵博超张羽
Owner BEIJING UNIV OF CHEM TECH
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